Deicing apparatus



April 7, 1942. E, 1 2,278,716

DEICI'NG APPARATUS Filed March 16, 1939 ATTORNEY.

so \faz 41 1s I v V m 7' as INVENTOR. 02? 7M 7 BY Patented Apr. 7, 1942 UNITED STATE DEICING APPARATUS Edgar L. Vail, New York, Inc.,

watch Company,

poration of New York Application March 16, 1939, Serial No. 262,132 9 Claims. (Cl. 244-134) This invention relates to deicing equipment, and more particularly to means whereby equipment of this kind is associated with a rotating mechanism to prevent ice from forming on the surfaces of said mechanism.

A well-known and undesirable phenomenon in aircraft operation is the formation of ice on the surfaces of the craft, and this condition is particularly objectionable when it occurs upon moving parts, such as a propeller constituting a part of an indicating instrument. Aircraft instruments of this type usually comprise an indicating unit in the codkpit operatively connected to a propeller unit mounted on the wing of the aircraft. If ice is formed on the propeller unit, the speed of the propeller is varied independently of the speed of the craft and the readings of the indicating unit are thus rendered inaccurate and N. Y., assignor to Jaeger New York, N. Y., a coruseless. Furthermore, the formation ofice on a o rotating body creates unbalanced centrifugal and inertia forces which set up vibrations creating excessive stresses which may render the entire unit inoperative.

It is accordingly an object of the present invention to provide novel deicing means in combination with a rotating member such as the propeller of an indicating device.

Another object is to provide, in combination with the propeller unit of an air speed indicator, a novel fluid ejecting mechanism which does not increase the wind resistance of said unit.

A further object is to provide a novel compact impeller unit adapted for effective and accurate operation at high altitudes and/or low temperatures.

Still another object is to provide a novel deicing mechanism which is positive in action and capable of producing a desired spray of antifreeze fluid over a selected surface or surfaces.

The above and other objects and novel features of this invention will more fully appearfrom the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however,

that the drawing is for purposes of illustration only and is not intended as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawing, wherein like reference characters refer to like parts throughout the several views,

Fig. l is a view, partly in elevation and partly in section, showing one form of the present invention in combination with an impeller unit;

.along line 3-3 of Fig.

Fig. 2 is a sectional view taken substantially along line 2--2 of Fig. 1; a

Fig. 3 is a sectional .view, taken substantially 1; Fig. 4 is a view, partly in elevation and partly in section, with parts broken away, showing;

somewhat diagrammatically, the above embodiment operatively associated with a source of antifreeze fluid; and,

Fig. 5 is an enlarged fragmentary section of a portion of the mechanism shown in Fig.- 1.

The single embodiment of the invention illustrated comprises a cylindrical casing Ill which is secured by suitable means to a plane wing (not,

shown) and has a bearing member or housing I l concentrically mounted therein and rigidly secured thereto by screws l2. Two bearings l3, each preferably sealed at one end and axially spaced by a separating sleeve M, are carried by said member and journal a hollow shaft l5 extending axially in both directions beyond member II and having a central portion iii of increased diameter, the edges of said portion engaging the plane faces of said bearings and fixing said shaft against axial movement. A huh I! is preferably keyed to the portion of shaft l5 extending, as viewed in the drawing, beyond the left end of member ii, and a plurality of propeller blades I8, two being shown in .the present embodiment, are securely fixed to said hub, preferably by a band I9, being spaced at equal distances around the circumference of said hub. The left end of said shaft isexternally threaded and a nut 20 is screwed thereon to axially secure said hub.

Hub l'l constitutes the leading end of the impeller unit and is provided with a cap 2| which is preferably secured to said hub by a force fit, and said hub and cap are shaped in accordance with well-known principles of streamlining in order to reduce the air resistance of said unit. A space or chamber 22 is thus created between said cap and said hub.

When the airplane upon which the impeller unit is mounted is in flight, propeller i1, i8 is rotated at an angular speed proportional to the speed of the plane and propels shaft i5 at the same speed. In order to convert this rotation into a speed reading on an instrument remote from said impeller, means are provided for in-' terrupting an electrical current at a frequency proportional to the shaft velocity. Said means preferably comprise a cylindrical member 23 of insulating material eccentrically mounted on a sleeve 24 secured to shaft and adapted to engage a pair of resilient contacts 25 (Fig. 2), each of the latter'being fixed at one end to a terminal 26 and having the other end urged into resilient engagement with'a terminal 21. Each of said terminals is secured to or formed with an annular insulation member 28 and the latter is in turn fixed to member ll. Each of said terminals also is electrically connected by insulatedconductors 29 (Fig. 1) to one of prongs 30 carried by an insulated socket 3|, the latter being fixed to and constituting the right end of the impeller unit. Eccentric 23, when rotating, moves contacts 25 radially and once during each revolution breaks the circuit between said contacts and terminals 21, thereby creating an interrupted circuit having a frequency corresponding to the angular speed of shaft l5. Suitable connecting means (not shown) may be provided to plug into socket II and to transmit current through the two circuits comprised by contacts 25 and terminals 28 and 21 from a source of electrical energy and to thereafter convey the interrupted current to a suitable indicating instrument.

It is fairly obvious that any increase in weight of the moving parts of the impeller unit, as by the formation of ice thereon, particularly when the weight is located to create unbalanced inertia and centrifugal forces, will materially change the angular speed of propeller l1, l8 for any given plane speed. This will render the impeller unit and the apparatus connected thereto ineffective and useless as a measuring instrumeiit. Accordingly, it is very important that formation of ice on the impeller parts, particularly on propeller ll, l8 and cap 2|, be prevented,

- and novel deicing means are provided and novelly combined with the impeller unit to keep the latter coated during flight with a suitable antiing It, being formed integrally with a pair of axially extending arms 44 which are, in turn, integral with a ring 45 encircling and secured to bearing member I, said ring being interposed between said member and said casing.

An opening it partly threaded. the unthresded portion thereof being conical in shape, is provided in su rt 42, being centrally located relative to casing l0, and tube 24 is adapted to extend radially to the center of said casing and then pass through said opening. In order to 13.:

freeze fluid, such as a mixture of glycerine and alcohol. As illustrated, said means comprise a reservoir or supply tank 22 (Fig. 4) containing said anti-freeze mixture under apressure preferably of about four or flve pounds per square inch above atmospheric, the pressure being maintained through a conduit 22 connecting said reservoir with a suitable high pressure source (not shown) associated with the engine, as, for example, a pump. Reservoir 22 is preferably mounted in a wing, and suitable control means in the form of a valve 34 are provided in conduit 33 within reach of the airplane operator whereby said reservoir may be disconnected from the source of pressure.

The anti-freeze fluid flows from reservoir 22 through a conduit 35 which is preferably flexible and which is connected by a coupling 20 to a tube 31 of a suitable flexible metal such as copper. Coupling 36 comprises a needle or conical valve 38 having a spring I! normally holding said valve in closed position and prevention any back flow of fluid from tube 31 to tube 35 and further prevent ing any flow from tube 25 to tube 31 unless the fluid in reservoir 28 is under pressure. Accordingly, since the pressure in said reservoir is only built up during operation of the airplane engine,

there is no flow of fluid when the engine is inoperative. Tube 21 flts snugly into an opening or slot 40 provided through socket 3| and extends through said opening into casing III. A fairly stiff capillary tube 4|, preferably of stainless steel, is connected to the end of tube, 21 by suitable means such as a coupling 42, the'latter being joined to said tubes by solder to form fluidtight connections therewith. A narrow bracket or support 43 extends diametrically across cassaid tube in central position, a clamp nut or screw 41 encircles said tube and is threaded in opening 46, being provided with a somewhat resilient conical tip which engages the conical wall of said opening and as said screw is threaded into said opening the tip is compressed radially and tightly grips tube 4|. From said clamp nut said tube is directed through hollow shaft l5 and extends beyond the end of said shaft into chamber 22 between cap 2| and hub IT.

The anti-freeze fluid which flows from reservoir 22 into chamber 22 is adapted to flll the latter and is prevented from flowing back through the space between tube 4| and hollow shaft I! by packing means associated with said tube and said shaft. Said means comprise a plurality of washers 48 (Fig. 5) of some suitable resilient material such as rubber or leather, the edges and walls of said washers being compressed in fluid tight engagement with the periphery of tube I by a nut 49 which is provided .with a shoulder 50. Nut 49 is screwed on the threaded end of shaft 18 and said washers are compressed and held between shoulder 50 and the end of shaft l5 and rotate with said shaft when the latter is driven by propeller l1, l8. In addition to minimizing leakage from chamber 22, washers 4| support the end of tube 4| maintaining said tube rigid and concentric with shaft II, and therefore keeping the same fromrubbing against the wall of said shaft.

In order to provide means for electing the anti-freeze fluid from chamber 22, asmall opening 5| (Fig. 1) about .01 inch in diameter is pro vided at the foremost tip of cap 2| and a plurality of openings 52 are located about the periphery of said cap in proximity to the Junction thereofbeing thereafter spread by the centrifugal forces acting thereon to the tips of the propeller blades.

In operation, the impeller unit is actuated by the wind flowing past propeller I1, I! at a relatively high speed, causing the latter to rotate and drive shaft I! at a rate determined by the'speed of the airplane upon which said impeller unit is mounted. Shaft It causes eccentric 22 to break each of two electric circuits comprised by contacts 25 and terminals 26 and 21, once for every revolution thereof, and these interrupted electrical currents are conducted from socket 2| to a remote indicating instrument to preferably provide a. visual record of the speed or distance of travel of the airplane.

The deicing equipment is set into operation with the airplane motor, the latter building up a pressure in reservoir 32 which overcomes the resistance of spring 39 permits the flow of anti-freeze fluid from said reservoir through conduits 35, 31 and Al to chamber 22. The fluid is thereafter ejected through openings iii and 52 and is caused to coat substantially the entire impeller unit surface, including stationary and moving parts. The flow of anti-freeze fluid is preferably continued during the entire flight, although the operator of the airplane may shut off reservoir 32 from the pressure source by means of valve 34, thus permitting spring 89 to close valve 38 and thereby prevent a further fluid flow.

There is thus provided a novel combination of deicing equipment with a streamlined unit whereby the latter is effectively coated with a film of anti-freeze fluid during flight, said equipment having no externally projecting members which tend to increase the air resistance of said unit. There is also provided a novel means for mounting deicing equipment in a rotary unit whereby the external moving parts of said unit are. sufficiently sprayed with anti-freeze fluid to prevent the formation of ice thereon. An impelier unit equ pped with the above invention becomes operable to actuate an indicating instrument accurately under-any atmospheric conditions and particularly under conditions which would, except for the present invention, cause the formation of ice on the moving parts of the impeller. complex nor a delicate apparatus and is accordingly easy to install and certain in operation, ready means forcontrolling said equipment being within easy reach of the airplane operator.

to open valve 38 and The deicing equipment is neither a.

voir of anti-freeze fluid, stationary communicating means extending through said first-named means and connecting said chamber t-o said reservoir, and valve means operativeiy associated with said connecting means.

4. In aircraft apparatus, a propeller mechanism, a streamlined member secured to said mechanism, a chamber being formed between said member and said mechanism, said member having openings therein connecting said chamber with the exterior of said member, means drivably connected to said mechanism to be driven thereby. means for interrupting an electric current mounted on said last-named means, a

Although only a single embodiment of the present. invention has been illustrated and described, it is to be expressly understood that the same is not limited thereto. For example, it will now be apparent to those skilled in the art that the deicing equipment. may be utilized with equal facility upon other rotating devices such as impeller units of thetype which transmit energy to the indicating instruments mechanically and not electrically. Furthermore, the connecting conduits from reservoir 32 to chamber 22 may be replaced by a single tube. Various other changes may be made without departing from the spirit and scope of the invention. For a definition of the invention, reference will be had primarily to the appended claims.

'What is claimed is:

1. In combination with a rotating unit to be deiced. a reservoir carried in front of said unit, a stationary hollow member extending through said unit and communicating with saidreservoir, and a source of anti-freeze fluid connected to said member.

2. The combination with an impeller unit of a means for preventing ice formation comprising a reservoir of anti-freeze fluid, a stationary conduit centrally located within said impeller unit, and fluid discharging means mounted on the front end of said impeller'unit, said fluid discharging means communicatingwith said reservoir through said conduit.

3. In aircraft apparatus, a propeller mechareservoir of anti-freeze fluid, means extending through said first-named means and connectingsaid reservoir and said chamber, and a valve mechanism interposed in said last named means.

5. The combination with an impeller unit having a chamber therein communicating with the external surface thereof of deicing means adapted to prevent ice from forming onsaid surface, said deicing means comprising a reservoir of anti-freeze fluid, a conduit from said reservoir to the interior of said unit, a valve mechanism operativeiy connected to said conduit to control the fluid flow therethrough, and a stationary tube extending centrally through said unit and connecting said conduit with said chamber.

6. In a propeller unit having a'proDeller and -a hub therefor, an anti-freeze fluid reservoir consisting of a stream-lined hub cap with a pluthe exterior of said propeller unit, one of said openings being located in the leading end of said unit approximately coincident with' the axis-of said unit. V

7. In aircraft apparatus, a propeller mechanism, a streamlined member isecured to said mechanism, a chamber being formed between said member and said mechanism said member having openings therein connecting said chamber with theexterior of said member, means drivably connected to said mechanism, a reservoir of anti-freeze fluid, stationary communicat-- ing means extending through said first-named means and connecting said chamber to said reservoir.

8. The combination with an impeller unit having a chamber therein communicating with the external surface thereof of deicing means adapted to prevent ice from forming-on said surface. said deicing means comprising a reservoir of anti-freeze fluid, a conduit from said reservoir to the interior of said unit. and a stationary tube extending centrally through said unit and connecting said conduit with said chamber.

9. In a propeller unit having a hub member, a hollow drive shaft and propeller blades secured to said hub member, a streamlined hub cap attached to the leading edge of said hub member to form a chamber between said cap and hub member, said hub cap being provided with discharge openings, a plurality of said openings benism, a streamlined member secured to said mechanism. a chamber being formed between said member and said mechanism,.said member 'having openings therein connecting said chaming located adjacent the periphery of said cap and at least one opening being located substantially at the foremost point of said cap, a reservoir of anti-freeze fluid, a conduit from said reservoir, and a stationary capillary tubeconnectsaid conduit with said-chamber, said tube said drive shaft.

extending centrally through EDGAR L. VAIL. 

